1. Field of the Invention
The present invention relates to an adsorbent, a porous filter, an air cleaning device, a method of cleaning air, and a method of manufacturing a porous filter. More specifically, the present invention relates to an adsorbent, a porous filter, an air cleaning device, a method of cleaning air, and a method of manufacturing a porous filter which can efficiently remove hazardous substances.
2. Description of the Background Art
In addition to a conventional problem of environmental pollution caused by a foul smell, a contaminant or a hazardous chemical substance which is industrially generated from a factory or a clean room, a problem of contamination of air inside a space for daily life, for example, a room or a car, by a hazardous substance such as a foul smell, a hazardous chemical substance, pollen, floating dust, or floating bacteria is becoming a big concern in recent years as demands for improved amenities increase, and therefore needs for removal of such hazardous substances are rapidly increasing. One of main reasons for such needs is that there are increasing number of people, one out of ten people for the present, who develop chemical sensitivity.
A common method for removing a hazardous substance such as a foul smell or a hazardous chemical in an environment is adsorption with an adsorbent formed with a porous material such as activated carbon or zeolite. Since conventional activated carbon has a specific surface area as small as a hundred to a few hundred m2/g, however, a removal property thereof rapidly decreases after it adsorbs a certain amount of the hazardous substance, or the hazardous substance once adsorbed may be released again depending on an environmental temperature or a concentration of the hazardous substance. Therefore, fibrous activated carbon having an increased specific surface area (generally 1500-1700 m2/g), for example, has been developed (see, for example, Japanese Patent Laying Open Nos. 2002-212838 and 2001-164430).